Psoriasis and rosacea are chronic inflammatory autoimmune skin disorders which affect a significant portion of people in the U.S. Although these disorders are not life-threatening, they can lead to a significantly poor quality of life and negatively impact the mental health of the patients, leading in severe cases to depression and even suicidal tendencies. There are five approved biological therapeutics on the market for psoriasis (none for rosacea), and all of these are systemic immune suppressors.
The hallmarks of psoriasis are the chronic formation of itchy and scaly plaques, excessive skin inflammation, and hyperkeratinization. The most common form is plaque psoriasis (psoriasis vulgaris), but there are numerous different clinical manifestations of psoriasis, including a form involving joint inflammation and another which affects the nails. The exact causes of psoriasis are unknown, but genetic predisposition and environmental stressors are implicated. Psoriasis affects 2-3% of the worldwide population, and 4.5 million people in the U.S. suffer from the disease. The current modes of treatment include topical corticosteroids or systemic biologics.
Rosacea is another autoimmune disease predominantly affecting the skin, which affects 14 million in the U.S. alone. The manifestations of rosacea include persistent reddening of the skin, mainly in the face, possibly accompanied by stinging, itching sensations, and/or swelling. The onset of rosacea is usually triggered by a wide variety of environmental stressors, including diet, exercise, or weather changes. LL37 may also play a significant role in systemic lupus erythematosus (SLE or “lupus”). Thus, targeting the peptide with a nucleic acid or nucleic acid-like inhibitor may prove to be a highly effective treatment.
Recent research has highlighted the overexpression of a 37-amino acid human antimicrobial peptide named LL37 in the pathogenesis of psoriasis, and independently implicated LL37 in rosacea.